A study on the isolation, screening and phosphate solubilizing capacity of phosphate solubilizing bacteria in the rhizosphere of corn.

Phosphate-solubilizing bacteria were isolated from the rhizosphere of corn,and 38 strains of inorganic phosphate-solubilizing bacteria and 35 strains of organic phosphate-solubilizing bacteria were screened by using traditional method of isolation and culture of microorganisms.The number of both total bacteria and phosphate-solubilizing bacteria in the rhizosphere soil was higher than that in the bulk soil.Major bacterial colony was milky or yellow,irregular or roughly round,smooth,thick,flat,non-transparent with ragged edge.Furhter study on phosphorus solubilizing capacity of the strains by Mo-Sb colorimetry method indicated that pH was significantly correlated with the content of available P of inorganic phosphate-solubilizing bacteria strains,but not correlated with that of organic phosphate-solubilizing bacteria strains.There were great differences between solubilizing calcium phosphate by inorganic phosphate-solubilizing bacteria and solubilizing lecithin by organic phosphate-solubilizing bacteria.Their phosphate-solubilizing capacity ranged from 8.88 to 108.31 and 0.51 to 3.53 mg/L,respectively.The strain SWJ1-4 and SWJ3-1 had a higher ability in solubilizing inorganic phosphate than other strains and strain RYJ1-6 had a higher capacity in solubilizing organic phosphate.The three strains had great potential in further development of microbiological fertilizer because of their stronger phosphate-solubilizing ability,faster growth rate and better growing state.